Preheat oven to 350 degrees F. Adjust oven rack to lower middle position. Spray one (1) 9x5-inch loaf pan with non-stick cooking spray.
In a large bowl, whisk together the flour, baking soda, and salt; set aside.
Place five (5) peeled bananas in a microwave-safe bowl; cover with plastic wrap and cut several steam vents in the plastic wrap with a paring knife. Microwave on high power until the bananas are soft and have released liquid, approximately 5 minutes.
Remove from microwave and transfer the bananas to a fine-mesh strainer placed over a medium-size bowl. Allow to drain, stirring occasionally, for 15 minute. You should have 1/2 to 3/4 cup liquid after straining. NOTE: I had a total 1 cup of banana liquid after straining. Set aside the remaining banana mixture in the strainer.
Transfer the banana liquid to a medium-size saucepan over medium heat. Let simmer until the banana liquid is reduced to 1/4 cup, approximately 5 minutes. NOTE: Since I had 1 cup of banana liquid to reduce, it took me 15 minutes to reduce the liquid to 1/4 cup.
Remove pan from heat and and stir the reduced banana liquid into the set aside banana mixture; mash with a potato masher until fairly smooth. NOTE: I put the banana mixture into my blender for a few seconds. Whisk in the melted butter, eggs, brown sugar, and vanilla extract.
Pour the banana mixture into the flour mixture and stir until just combined with some streaks of flour remaining. Gently fold in the walnuts or pecans.
Pour the batter into the prepared bread pan. Slice the remaining peeled banana diagonally into 1/4-inch-thick slices. Shingle the banana sliced on top of both sides of the loaf, leaving 1 1/2-inc-wide space down the center to ensure even rising. Sprinkle the 2 teaspoon sugar evenly over the top of the loaf.
Bake 50 to to 60 minutes or until a toothpick inserted in the center comes out clean. NOTE: Be sure and poke the toothpick already to the center of the loaf. A good check is to use an instant digital thermometer to test your bread. The internal temperature of the bread should be at 200 degrees F. when done.
Remove from oven and cool on a wire rack 10 minutes; remove from pan. Cool completely before slicing.
Makes one (1) loaf.
* To ripen bananas, allow green or yellow bananas to ripen at room temperature until the skin is covered with brown spots. Do not even think of making banana bread with anything less than very ripe, heavily speckled fruit - unless you are fine with a bland loaf.
Ultimate Banana Bread Recipe: https://whatscookingamerica.net/bread/ultimatebananabread.htm